Head-Mounted Display Apparatus

1. A head-mounted display apparatus comprising: an image display device; a wearing device with which the image display device is worn on a head of an observer; and an attachment member with which the image display device is attached to the wearing device, wherein the attachment member includes a first balls; a support member having a first linear groove; a retaining member having a fourth linear groove extending in a different direction from the first groove; and urging means urging the retaining member against the support member, wherein, in a state where the retaining member is urged against the support member by the urging means, the first ball fits into the first and fourth grooves, wherein the image display device is attached to the support member, and wherein the wearing device is attached to the retaining member.

2. The head-mounted display apparatus according to claim 1 , wherein the first linear groove and the fourth linear groove include consecutive depressions respectively.

3. A head-mounted display apparatus comprising: an image display device; a wearing device with which the image display device is worn on a head of an observer; and an attachment member with which the image display device is attached to the wearing device, wherein the attachment member includes first, second, and third balls; a support member having a first linear groove including consecutive depressions, a second linear groove parallel to the first groove and including consecutive depressions, and a third linear groove parallel to the first groove and including consecutive depressions; a retaining member having a fourth linear groove orthogonal to the first groove and including consecutive depressions, a fifth linear groove parallel to the fourth groove and including consecutive depressions, and a sixth linear groove parallel to the fourth groove and including consecutive depressions; and urging means urging the retaining member against the support member, wherein, in a state where the retaining member is urged against the support member by the urging means, the first ball fits into the first and fourth grooves, the second ball fits into the second and fifth grooves, and the third ball fits into the third and sixth grooves, with the first to third balls being positioned at respective apexes of a virtual triangle, wherein the image display device is attached to the support member, and wherein the wearing device is attached to the retaining member.

4. The head-mounted display apparatus according to claim 3 , wherein a guide member is provided between the support member and the retaining member, the guide member having receiving portions that receive the first to third balls, respectively.

5. The head-mounted display apparatus according to claim 3 , wherein the first and fourth grooves are spot-faced so that the first ball is received stably, wherein the second and fifth grooves are spot-faced so that the second ball is received stably, and wherein the third and sixth grooves are spot-faced so that the third ball is received stably.

6. The head-mounted display apparatus according to claim 3 , wherein the image display device and the attachment member are provided for each of right and left eyes.

7. The head-mounted display apparatus according to claim 3 , wherein the image display device includes an image generator; and an optical device receiving light from the image generator, guiding the light, and outputting the light toward a corresponding one of the eyes of the observer.

8. The head-mounted display apparatus according to claim 7 , wherein the optical device includes a light-guiding plate causing the received light to propagate with total reflection thereinside before outputting the light; first deflecting means deflecting the light received by the light-guiding plate so that the light is totally reflected inside the light-guiding plate; and second deflecting means deflecting, a plurality of times, the light caused to propagate with total reflection inside the light-guiding plate so that the light is output from the light-guiding plate.

9. The head-mounted display apparatus according to claim 8 , wherein the first deflecting means reflects the light received by the light-guiding plate, and wherein the second deflecting means transmits and reflects, a plurality of times, the light caused to propagate with total reflection inside the light-guiding plate.

10. The head-mounted display apparatus according to claim 9 , wherein the first deflecting means functions as a reflective mirror, and wherein the second deflecting means functions as a transflective mirror.

11. The head-mounted display apparatus according to claim 8 , wherein the first deflecting means diffracts the light received by the light-guiding plate, and wherein the second deflecting means diffracts, a plurality of times, the light caused to propagate with total reflection inside the light-guiding plate.

12. The head-mounted display apparatus according to claim 11 , wherein the first and second deflecting means include diffraction grating elements.

13. The head-mounted display apparatus according to claim 12 , wherein the diffraction grating elements are reflective diffraction grating elements.

14. The head-mounted display apparatus according to claim 12 , wherein the diffraction grating elements are transmissive diffraction grating elements.

15. The head-mounted display apparatus according to claim 12 , wherein one of the diffraction grating elements is a reflective diffraction grating element and the other is a transmissive diffraction grating element.

16. The head-mounted display apparatus according to claim 7 , wherein the optical device includes a transflective minor receiving the light from the image generator and outputting the light toward the eye of the observer.

17. The head-mounted display apparatus according to claim 7 , wherein the image generator includes an image-forming device having a plurality of pixels arranged in a two-dimensional matrix; and a collimating optical system collimating the light from the pixels of the image-forming device into parallel light and outputting the parallel light.

18. The head-mounted display apparatus according to claim 7 , wherein the image generator includes a light source; a collimating optical system collimating light from the light source into parallel light; scanning means scanningly moving the parallel light from the collimating optical system; and a relay optical system relaying and outputting the parallel light scanningly moved by the scanning means.

19. The head-mounted display apparatus according to claim 3 , wherein the wearing device forms a frame of a pair of glasses.

20. The head-mounted display apparatus according to claim 19 , wherein the frame includes a front member to be positioned in front of the observer; and two temples turnably attached to respective ends of the front member with hinges, and wherein the attachment member is attached to each of the ends of the front member.